With the progress of society and technology, human beings have progressively increased reliance on electric power. Electric power is mostly obtained by conversion from petroleum or the coal. Due to the gradual exhaustion of energy resources, the significantly increased price of petroleum, and the increase of environmental consciousness, numerous alternative energy resources such as solar power, wind force, and fuel cells have recently been proposed, so as to reduce the dependence on petroleum and coal.
However, the existing alternative energy resources can only output direct current power which has a voltage of about 12 volts. For the purpose of supplying electric power for illumination devices of courtyards, factories, residences offices, restaurants/stores, night streetlamps, or department stores/superstores, the electric power must be first converted into alternating current (AC) power . In addition a high actuation voltage of about 500-680 volts and a working voltage of about 200-380 volts, required for persistent illumination, must also be supplied for the illumination devices. In fact, the process of converting direct current into alternating current causes a 20 percent energy loss, resulting in an unnecessary loss of energy resources.